Fatty acids and TxA2 generation, in the absence of platelet-COX-1 activity

Background and aims: Omega-3 fatty acids suppress Thromboxane A(2) (TxA(2)) generation via mechanisms independent to that of aspirin therapy. We sought to evaluate whether baseline omega-3 fatty acid levels influence arachidonic acid proven platelet-cyclooxygenase-1 (COX-1) independent TxA(2) generation (TxA(2) generation despite adequate aspirin use). Methods and results: Subjects with acute myocardial infarction, stable CVD or at high risk for CVD, on adequate aspirin therapy were included in this study. Adequate aspirin action was defined as complete inhibition of platelet-COX-1 activity as assessed by <10% change in light transmission aggregometry to >= 1 mmol/L arachidonic acid. TxA(2) production was measured via liquid chromatography-tandem mass spectrometry for the stable TxA(2) metabolite 11-dehydro-thromboxane B-2 (UTxB(2)) in urine. The relationship between baseline fatty acids, demographics and UTxB(2) were evaluated. Baseline omega-3 fatty acid levels were not associated with UTxB(2) concentration. However, smoking was associated with UTxB(2) in this study. Conclusion: Baseline omega-3 fatty acid levels do not influence TxA(2) generation inpatients with or at high risk for CVD receiving adequate aspirin therapy. The association of smoking and TxA(2) generation, in the absence of platelet COX-1 activity, among aspirin treated patients warrants further study. (C) 2013 Elsevier B. V. All rights reserved.